.\"-
.\" Copyright (c) 2022 Tetsuya Uemura <t_uemura@macome.co.jp>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.Dd November 18, 2022
.Dt WDATWD 4
.Os
.Sh NAME
.Nm wdatwd
.Nd device driver for the ACPI WDAT based watchdog interrupt timer
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device wdatwd"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
wdatwd_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides
.Xr watchdog 4
support for the watchdog interrupt timer in ACPI WDAT (Watchdog Action Table).
.Pp
Since WDAT itself is an abstraction for the real hardware such as ICH WDT, it
must be noted that only one driver can be used at a time, either the real
hardware specific driver or this driver.
.Sh SYSCTL VARIABLES
The following read-only
.Xr sysctl 8
variables are available:
.Bl -tag -width indent
.It Va dev.wdatwd.%d.running
The status of the watchdog timer. 0 if not running, or 1 if running.
.It Va dev.wdatwd.%d.timeout
The current value of the watchdog timeout in millisecond.
This can be 0 on some systems, and the zero value means that the default
timeout is used.
.It Va dev.wdatwd.%d.timeout_configurable
Whether the timeout is configurable or not.
It is 0 if configurable or any positive value if not.
.It Va dev.wdatwd.%d.timeout_default
The default value of the watchdog timeout in millisecond if any.
.El
.Sh SEE ALSO
.Xr ichwd 4 ,
.Xr watchdog 4 ,
.Xr watchdog 8 ,
.Xr watchdogd 8 ,
.Xr watchdog 9
.Rs
.%T Hardware Watchdog Timers Design Specification
.%R Requirements for Hardware Watchdog Timers Supported by Microsoft(R) Windows Vista(R) and Microsoft Windows Server(R) 2008 Operating Systems
.%A Microsoft Corporation
.%U http://msdn.microsoft.com/en-us/windows/hardware/gg463320.aspx
.%D 2006
.Re
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Tetsuya Uemura Aq Mt t_uemura@macome.co.jp
of MACOME, Corporation.
